apps/fat/bootsector.h

   1 /*
   2     fat - A FAT* CDI driver
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU Lesser General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #ifndef _BOOTSECTOR_H_
  20 #define _BOOTSECTOR_H_
  21
  22 #include <stdint.h>
  23
  24 #include "fat_cdi.h"
  25
  26 #define FAT_BOOTSECTOR_START 0
  27
  28 #define fat_num_sectors(bs) ((bs)->num_sectors_small!=0?(bs)->num_sectors_small:(bs)->num_sectors)
  29
  30 #define fat_fat_start(bs,n) (((uint64_t)(bs)->reserved_sectors)*(bs)->sector_size+fat_fat_size(bs)*n)
  31 #define fat_fat_sectors(bs) ((uint64_t)((bs)->fat_size_small!=0?(bs)->fat_size_small:(bs)->fat32.fat_size))
  32 #define fat_fat_size(bs)    (fat_fat_sectors(bs)*(bs)->sector_size)
  33
  34 /// FAT bootsector
  35 struct fat_bootsector {
  36   /// Jump code
  37   uint8_t jump_code[3];
  38
  39   /// OEM name
  40   uint8_t oem_name[8];
  41
  42   /// Sector size
  43   uint16_t sector_size;
  44
  45   /// Sectors per Cluster
  46   uint8_t cluster_size;
  47
  48   /// Reserved sectors
  49   uint16_t reserved_sectors;
  50
  51   /// FAT copies
  52   uint8_t num_fats;
  53
  54   /// Maximum amount of directory entries in root directory
  55   uint16_t rootdir_max_ent;
  56
  57   /// Absolute amount of sectors (small)
  58   uint16_t num_sectors_small;
  59
  60   /// Media Descriptor Byte
  61   uint8_t media_desc;
  62
  63   /// Sectors per FAT (small)
  64   uint16_t fat_size_small;
  65
  66   /// Sectors per Track
  67   uint16_t track_size;
  68
  69   /// Heads
  70   uint16_t num_heads;
  71
  72   /// Sectors between MBR and boot sector
  73   uint32_t hidden_sectors;
  74
  75   /// Absolute amount of sectors
  76   uint32_t num_sectors;
  77
  78   union {
  79     struct {
  80       /// Bios driver number
  81       uint8_t bios_drive;
  82
  83       /// Reserved
  84       uint8_t res0;
  85
  86       /// Extended boot signature
  87       uint8_t ext_bootsig;
  88
  89       /// Filesystem ID
  90       uint32_t fs_id;
  91
  92       /// Filesystem Name
  93       uint8_t fs_name[11];
  94
  95       /// FAT type
  96       uint8_t fat_type[8];
  97
  98       /// Bootloader code
  99       uint8_t bootloader_code[448];
 100
 101       /// Boot signature
 102       uint8_t bootsig[2];
 103     }  __attribute__ ((packed)) fat12_16;
 104     struct {
 105       /// Sectors per FAT
 106       uint32_t fat_size;
 107
 108       /// FAT flags
 109       uint16_t fat_flags;
 110
 111       /// FAT32 version
 112       uint16_t fat32_version;
 113
 114       /// Cluster of root directory
 115       uint32_t root_cluster;
 116
 117       /// FS information sector
 118       uint16_t info_sector;
 119
 120       /// Sector of bootsector copy
 121       uint16_t bootsector_copy;
 122
 123       /// Reserved
 124       uint32_t res0[3];
 125
 126       /// Bios driver number
 127       uint8_t bios_drive;
 128
 129       /// Reserved
 130       uint8_t res1;
 131
 132       /// Extended boot signature
 133       uint8_t ext_bootsig;
 134
 135       /// Filesystem ID
 136       uint32_t fs_id;
 137
 138       /// Filesystem Name
 139       uint8_t fs_name[11];
 140
 141       /// FAT type
 142       uint8_t fat_type[8];
 143
 144       /// Bootloader code
 145       uint8_t bootloader_code[420];
 146
 147       /// Boot signature
 148       uint8_t bootsig[2];
 149     }  __attribute__ ((packed)) fat32;
 150   };
 151 } __attribute__ ((packed));
 152
 153 struct fat_bootsector *fat_bootsector_load(struct cdi_fs_filesystem *fs);
 154
 155 #endif